BRUSSELS, September 11. /ITAR-TASS/. The EU ambassadors have made a decision the new package of sanctions against Russia will take effect as of September 12, a source in the EU foreign policy service said Thursday.

“The decision is ready. New sanctions will take effect tomorrow, on September 12, when they are published in the Official Journal of the European Union,” the source said.

At the same time the official added that they may be revised or cancelled altogether depending on the march of events in Ukraine.

“In particular, it will depend on the observance of the ceasefire agreement and on implementation of the settlement plan,” the source said.

According to Western media, the new sanctions are applicable to three Russian oil majors - Rosneft, Transneft and Gazprom neft, as well as several holding companies in the arms manufacturing sector.

Also, sanctions may hit such Russian arms manufacturers as Uralvagonzavod, Oboronprom and United Aircraft-building Corporation.

The European Union plans to cut the maximum period of Russian bonds’ circulation in the 28 EU countries to 30 days from 90.

According to media reports, no less than 20 individuals will be added to the black list for Russia and Ukraine.

A European diplomatic source told ITAR-TASS earlier that at least four EU countries had spoken during the meeting for delaying the discussion until next week.

He said the situation in Ukraine showed that most of the forces involved in the conflict in eastern Ukraine were observing the ceasefire and this was a real relaxation of tensions for the first time since the outbreak of the conflict.

The four countries said new sanctions against Russia would send it the wrong signal.

Furthermore, there are other EU countries whose positions have not been clearly determined yet, the source said but declined to provide further details, saying the discussion was going on behind closed doors.

The West started to impose sanctions on Russia in March 2014 over the events in Ukraine. First, an early EU summit paused the talks on a visaless regime and a new base agreement on Russia-EU cooperation. Further on the sanctions were grouped into three categories - personal, corporate and sectoral. By the beginning of September some 420 Russian individuals and 143 companies had been put on the sanction lists of the European Union, the United States, Canada, Australia, Japan, Switzerland and Norway.

The sectoral restrictions, introduced for a period of twelve months, include embargoes on the supplies of military hardware to Russia, on the import of Russian armaments and related items, a ban on the export of dual purpose goods and know-hows, and on providing technologies and equipment for the oil and gas industry.

The latest political decision to tighten sanctions was made at the EU summit on August 30, and on September a panel of EU permanent representatives agreed that package of sanctions but refrained from effecting it for a while, as Kiev and the self-proclaimed Donetsk and Lugansk people’s republics concluded a cease-fire agreement.